The present invention relates to a holding fastener suitable for fastening a sheet-like or plate-like attachment member such as a silencer board (noise insulating board) of automobiles to a mounting member such as an automobile body.
Various holding fasteners have been known to assemble the sheet-like member such as a silencer board to another mounting member such as an automobile body. For instance, such holding fasteners are described in Japanese Utility Model Laid-Open No. 59-92213, Japanese Utility Model Laid-Open No. 62-45412, European Patent No. 0717202 and Japanese Patent Laid-Open No. 09-042247. In these conventional holding fasteners for the sheet-like member, the holding fastener is attached to the sheet-like member with pressing one surface of the sheet-like member by a flange or the like of the fastener and pressing the other surface of the sheet-like member by a pantograph-shaped foldable arm of the fastener. Thus, the holding fastener may be pre-assembled to the sheet-like member and the sheet-like member may be readily attached to the automobile body by aligning the holding fastener with a stud bolt projectingly disposed on the automobile body and then simply pushing in the holding fastener as-is. However, for pre-assembling such holding fasteners to the sheet-like member, an operation for folding the pantograph-shaped arm is required. Further, this operation undesirably is required to be done from the reverse side to the inserting direction of the holding fastener (i.e. from the backside of the sheet-like member). Japanese Patent Laid-Open No. 09-042247 describes that the assembling operation may be carried out from one side of the attachment member. However, this describes in connection with a case that an attachment member is positioned to a stud bolt of another mounting member without pre-assembling a holding fastener and the holding fastener is then pushed into the stud bolt. Thus, if the holding fastener is pre-assembled to the attachment member, it will be necessary to access the backside of the attachment member to fold the pantograph as with the holding fasteners described in the aforementioned other publications.
Japanese Patent Laid-Open No. 08-054010 discloses a clip having a flange disposed at a lower end of a shank of the clip and a flexible engagement arm which extends upward and closely along the shank and has an upper end portion projecting downward and radially outward. This clip may be attached to the attachment member only by an operation of inserting the clip into an insertion hole of the attachment member with making the side of the engagement arm forefront. Thus, the clip may be pre-assembled to the attachment member. However, in order to assure a sufficient engagement area of the flexible engagement arm to the attachment member, it is unavoidable to make the engagement arm longer and the projected amount of the clip from the attachment member is increased in proportion to the increased length of the engagement arm. As a result, it is necessary to secure an additional space over the surface of the attachment member in proportion to the increased projected amount. U.S. Pat. No. 5,991,984 discloses a holding fastener having a pair of holding pieces pivotably or rotatably formed at the end of a shank of the holding fastener wherein the holding pieces are manually rotated to be brought into contact with one surface of an attachment member. This holding fastener is structurally difficult to pre-assemble to the attachment member. Further, if it is intended to pre-assemble the holding fastener by enlarging its flange, it is impossible to achieve the assembling operation from one side of the attaching member.
Thus, it has been desired to provide a holding fastener capable of being pre-assembled to a silencer board, etc through the operation from one side of the silencer board, etc, and capable of keeping the dimension over the attachment member in a small level.
It is an object of the present invention to provide a holding fastener capable of being attached to a sheet-like attachment member such as a silencer board from one side of the attachment member in a pre-assembling operation for attaching the fastener to the attachment member, and capable of reducing the projected amount of the attached fastener from the attachment member to provide a space saving assembly. Also, it is an object of the present invention to provide a holding fastener that is inexpensive to manufacture, reliable to use and simple to install.
In order to achieve the above object, according to the present invention, there is provided a holding fastener to be connected to an attachment member comprising a shank adapted to be inserted into a mounting hole of an attachment member; a first holding portion disposed at one end of the shank and adapted to extend radially and outward from the mounting hole of the attachment member to hold one surface of the attachment member; a second holding portion disposed at the other end of the shank and adapted to hold the other surface of the attachment member, the second holding portion including a holding piece connected to the shank through a hinge to allow the holding piece to be pivoted or rotated between an insertion position that extends along the axis of the shank and a holding position that extends orthogonal to the axis of the shank; the shank includes a hollow portion; and an insertion tube is provided at the one end of the shank and adapted to be inserted axially into the hollow portion of the shank from the side of the first holding portion to the side of the second holding portion, wherein the holding piece and the insertion tube are cooperatively formed so that the end of the insertion tube inserted into the hollow portion of the shank allows the holding piece to be rotated from the insertion position to the holding position to be locked at the holding position. Thus, it is only necessary to insert the shank into the mounting hole from one side of the attachment member and inserting the insertion tube into the shank from the same said one side of the attachment member, the holding piece is folded down to the holding position at the side of the end of the shank to contact in parallel with the surface of the attachment member and is locked to the attachment member on the side opposite the said one side of the attachment member engaged and held by the first holding portion. In addition, since the holding piece contacts in parallel with the surface of the attachment member, the projection over the attachment member is minimized to provide a space saving assembly.
Preferably, the above holding fastener is a plastic one-piece product. In the holding fastener, there are preferably provided a pair of holding pieces opposed to each other in the diametrical direction of the shank to provide a uniform and sufficient holding power. Further, a section of each holding piece adjacent to the corresponding hinge is preferably formed as an insertion tube engagement portion at the insertion position, wherein the insertion tube engagement portion is adapted to be contacted with and pushed out by the end of the insertion tube to rotate each the holding piece from the insertion position to the holding position about the hinge to lock each the holding piece in assembled position.
Preferably, the insertion tube is integrally held to the shank through a connection piece extending from a portion of the shank adjacent to the first holding portion. A pair of the connection pieces are preferably opposed to each other in the diametrical direction of the shank, wherein each the connection piece includes integral hinges at a connected section to the shank, another connected section to the insertion tube and an intermediate section between both the connected sections, wherein the insertion tube is held in a posture and position so that the insertion tube can be axially slid into the shank from the side of the first holding portion to the side of the second holding portion. Thus, the insertion tube may be readily inserted by pushing in from the one side of the attachment member.
Preferably, the insertion tube includes a hollow portion to allow a stud bolt to be inserted thereinto, wherein the insertion tube includes an engagement pawl adapted to engage with a thread of the stud bolt. Preferably, the end of the engagement pawl is located outside the outer periphery of the insertion tube before the insertion tube is inserted into the shank; and when the insertion tube is inserted into the shank, the engagement pawl is moved toward the inside of the insertion tube by the inner wall of the shank to position the end of the engagement pawl at the inside beyond the inner wall of the hollow portion of the insertion tube. This provides more increased engagement force of the engagement pawl to the stud bolt.
The insertion tube preferably includes fastening means for attaching the attachment member to another mounting member, provided at the end on the opposite side of the end of the insertion tube inserted into the shank. A typical example of the fastening means includes an anchor-shaped fastening portion.